Search results for "neurotransmission"

2015

Polyunsaturated fatty acids (PUFAs) are essential nutrients for animals and necessary for the normal functioning of the nervous system. A lack of PUFAs can result from the consumption of a deficient diet or genetic factors, which impact PUFA uptake and metabolism. Both can cause synaptic dysfunction, which is associated with numerous disorders. However, there is a knowledge gap linking these neuronal dysfunctions and their underlying molecular mechanisms. Because of its genetic manipulability and its easy, fast, and cheap breeding, Drosophila melanogaster has emerged as an excellent model organism for genetic screens, helping to identify the genetic bases of such events. As a first step tow…

Allosterically potentiating ligands of nicotinic receptors as a treatment strategy for Alzheimer's disease.

2000

Abstract One of the most prominent cholinergic deficit in Alzheimer’s disease (AD) is the reduced number of nicotinic acetylcholine receptors (nAChR) in the hippocampus and cortex of AD patients, as compared to age-matched controls. This deficit results in reduced nicotinic cholinergic excitation which may not only impair postsynaptic depolarization but also presynaptic neurotransmitter release and Ca 2+ -dependent intracellular signaling, including transcriptional activity. Presently, the most common approach to correct the nicotinic cholinergic deficit in AD is the application of cholinesterase inhibitors. Due to the resulting increase in synaptic acetylcholine levels, both in concentrati…

Sodium dynamics: another key to astroglial excitability?

2012

Astroglial excitability is largely mediated by fluctuations in intracellular ion concentrations. In addition to generally acknowledged Ca 2+ excitability of astroglia, recent studies have demonstrated that neuronal activity triggers transient increases in the cytosolic Na + concentration ([Na + ] i ) in perisynaptic astrocytes. These [Na + ] i transients are controlled by multiple Na + -permeable channels and Na + -dependent transporters; spatiotemporally organized [Na + ] i dynamics in turn regulate diverse astroglial homeostatic responses such as metabolic/signaling utilization of lactate and glutamate, transmembrane transport of neurotransmitters and K + buffering. In particular, near-me…

Long term effects of peripubertal stress on excitatory and inhibitory circuits in the prefrontal cortex of male and female mice.

2021

Abstract The impact of stressful events is especially important during early life, because certain cortical regions, especially the prefrontal cortex (PFC), are still developing. Consequently, aversive experiences that occur during the peripubertal period can cause long-term alterations in neural connectivity, physiology and related behaviors. Although sex influences the stress response and women are more likely to develop stress-related psychiatric disorders, knowledge about the effects of stress on females is still limited. In order to analyze the long-term effects of peripubertal stress (PPS) on the excitatory and inhibitory circuitry of the adult PFC, and whether these effects are sex-d…

Post-weaning social isolation rearing influences the expression of molecules related to inhibitory neurotransmission and structural plasticity in the…

2012

Several lines of evidence indicate that alterations in the structure of neural circuits and inhibitory neurotransmission underlie the physiopathogenesis of schizophrenia. Most of the studies on these parameters have been focused on cortical regions and, despite the crucial role of the amygdala in this psychiatric disorder, there is less information on this region. In order to expand this knowledge, we have studied the expression of molecules related to inhibitory neurotransmission and structural plasticity in rats subjected to post-weaning isolation rearing, an animal model that reproduces several core symptoms of schizophrenia. We have analyzed, using qRT-PCR and immunohistochemistry, the …

Postsynaptic NO/cGMP Increases NMDA Receptor Currents via Hyperpolarization-Activated Cyclic Nucleotide-Gated Channels in the Hippocampus

2013

The nitric oxide (NO)/cyclic guanosine monophosphate (cGMP) signaling cascade participates in the modulation of synaptic transmission. The effects of NO are mediated by the NO-sensitive cGMP-forming guanylyl cyclases (NO-GCs), which exist in 2 isoforms with indistinguishable regulatory properties. The lack of long-term potentiation (LTP) in knock-out (KO) mice deficient in either one of the NO-GC isoforms indicates the contribution of both NO-GCs to LTP. Recently, we showed that the NO-GC1 isoform is located presynaptically in glutamatergic neurons and increases the glutamate release via hyperpolarization-activated cyclic nucleotide (HCN)-gated channels in the hippocampus. Electrophysiologi…

A subset of ventral tegmental area dopamine neurons responds to acute ethanol

2015

The mechanisms by which alcohol drinking promotes addiction in humans and self-administration in rodents remain obscure, but it is well known that alcohol can enhance dopamine (DA) neurotransmission from neurons of the ventral tegmental area (VTA) and increase DA levels within the nucleus accumbens and prefrontal cortex. We recorded from identified DA neuronal cell bodies within ventral midbrain slices prepared from a transgenic mouse line (TH-GFP) using long-term stable extracellular recordings in a variety of locations and carefully mapped the responses to applied ethanol (EtOH). We identified a subset of DA neurons in the medial VTA located within the rostral linear and interfascicular n…

Three Patterns of Oscillatory Activity Differentially Synchronize Developing Neocortical Networks In Vivo

2009

Coordinated patterns of electrical activity are important for the early development of sensory systems. The spatiotemporal dynamics of these early activity patterns and the role of the peripheral sensory input for their generation are essentially unknown. We performed extracellular multielectrode recordings in the somatosensory cortex of postnatal day 0 to 7 rats in vivo and observed three distinct patterns of synchronized oscillatory activity. (1) Spontaneous and periphery-driven spindle bursts of 1-2 s in duration and approximately 10 Hz in frequency occurred approximately every 10 s. (2) Spontaneous and sensory-driven gamma oscillations of 150-300 ms duration and 30-40 Hz in frequency oc…

Effects of (+)-tubocurarine on [3H]acetylcholine release from the rat phrenic nerve at different stimulation frequencies and train lengths

1987

The effect of (+)-tubocurarine (TC) on the release of [3H]acetylcholine from the rat phrenic nerve-hemidiaphragm preincubated with [3H]choline was investigated at different stimulation frequencies and train lengths. At 0.5 Hz (100 pulses) TC failed to modulate the evoked acetylcholine release. A slight (30%) inhibition was observed at 1 Hz (100 pulses). Release of acetylcholine evoked at 5, 25 and 50 Hz (100 pulses) or 100 Hz (200 pulses) was markedly reduced by TC. The degree of inhibition (60%) was similar between 5 Hz and 100 Hz. A concentration of 1 mumol/l TC was a maximal effective concentration at 5 Hz whilst at all higher stimulation frequencies a 10-fold higher concentration was ne…

NO as a signalling molecule in the nervous system

2002

The discovery that nitric oxide (NO) functions as a signalling molecule in the nervous system has radically changed the concept of neural communication. Indeed, the adoption of the term nitrergic for nerves whose transmitter function depends on the release of NO or for transmission mechanisms brought about by NO (Moncada et al., 1997) emphasizes the specific characteristics of this mediator. The physical properties of NO prevent its storage in lipid-lined vesicles and metabolism by hydrolytic degradatory enzymes. Therefore, unlike established neurotransmitters, NO is synthesized on demand and is neither stored in synaptic vesicles nor released by exocytosis, but simply diffuses from nerve t…